not to start an argument but, how about, "once it can live outside the womb, it's a human being." ? ![[popcorn]](http://www.armedpolitesociety.com/Smileys/default/mf_popcorn.gif "Popcorn")
Once it can live outside... under what conditions? In a petri dish? In a (not yet invented) artificial womb? In a NICU?
If a legal guardian has the right to reject medical care due to religious objections, does that include the right to forbid a hospital from placing a newborn in a NICU? IOW, are you willing to violate someone else's freedom of religion in order to satisfy your moral concept that everything that can be done must be done to bring a child into the world once it reaches 5-6 months, or else it's murder?
What happens when artificial wombs exist? The concept that "this foetus might survive outside the womb with some weeks/months of life support, so abortion is murder" becomes "this embryo can grow to viability in vitro so discarding it is murder" and then "this egg and sperm from an egg and sperm bank can be combined and grow to viability, so discarding any gamete is half murder, too."
Posit: the way each of us views conception and abortion depends a lot on whether we view conception as something magical/soul-conferring or as just another biological process. And if it is magical/soul-conferring, then that also presumes in some way that non-human animal conception isn't magical/soul-conferring, or if there is a soul involved, it's not the same grade of soul that humans get at conception.
